Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2105.14160 · Physical Review A

Spatiotemporal mode-selective quantum frequency converter

Santosh Kumar, He Zhang, Prajnesh Kumar, Malvika Garikapati, Yong Meng Sua, Yu‐Ping Huang

Published Aug 6, 2021• 12 citations
arXivHTMLPDF

Abstract

We experimentally demonstrate a mode-selective quantum frequency converter over a compound spatiotemporal Hilbert space. We show that our method can achieve high extinction for high-dimensional quantum state tomography by selectively upconverting the signal modes with a modulated and delayed pump. By preparing the pump in optimized modes through adaptive feedback control, selective frequency conversion is demonstrated with up to 30 dB extinction. The simultaneous operations over high-dimensional degrees of freedom in both spatial and temporal domains can serve as a viable resource for photon-efficient quantum communications and computation.

DOI
10.1103/physreva.104.023506

Related papers

A Programmable Spatiotemporal Quantum Parametric Mode Sorter

Malvika Garikapati, Santosh Kumar, He Zhang +2 more

We experimentally demonstrate a programmable parametric mode sorter of high-dimensional signals in a composite spatiotemporal Hilbert space through mode-selective quantum frequency up-conversion. As a concrete example and with quantum communication applications in mind, we consider the Laguerre-Gaussian and Hermite-Gaussian modes as the spatial and temporal state basis for the signals, respectively. By modulating the spatiotemporal profiles of the up-conversion pump, we demonstrate the faithful selection of single photons in those modes and their superposition modes. Our results show an improvement in the quantum mode-sorting performance by coupling the up-converted light into a single-mode fiber and/or operating the upconversion at the edge of phase matching. By optimizing pump temporal profiles only, we achieve more than 12 dB extinction for mutually unbiased basis (MUB) sets of the spatiotemporal modes. This fully programmable and efficient system could serve as a viable resource for quantum communications, quantum computation, and quantum metrology.

arXiv:2210.16517•Oct 29, 2022•1 citation

Spatiotemporal quantum parametric mode sorter

Santosh Kumar, Malvika Garikapati, He Zhang +2 more

We demonstrate a spatio-temporal quantum parametric mode sorter that can achieve high extinction by selectively upconverting the signal modes with an optimized pump. This could serve as a viable resource for photon-efficient quantum communication and computation.

Conference on Lasers and Electro-Optics•Jan 1, 2022•0 citations

Spatial-mode-selective quantum frequency conversion (Conference Presentation)

Young Bong Kwon, M. Giribabu, Lu Li +4 more

Spatial-mode-selective frequency conversion is potentially useful for both classical and quantum communication applications. By a judicious choice of the quasi-phase-matching period in a Kai(2) multimode waveguide, such conversion can be achieved with high efficiency (close to 100%) and with low crosstalk (< -20 dB). For space-division multiplexing application with classical signals, where each spatial mode represents a separate signal channel, the selective conversion of a spatial mode without disrupting other signal modes can be used for reconfigurable spatial-mode de-multiplexing. This classical de-multiplexing capability can be also extended to the quantum regime, where the quantum state of the signal is preserved during frequency conversion, owing to the unitary nature of the sum-frequency generation (SFG) process. Building upon our previous experimental demonstration of the classical spatial-mode-selective frequency up-conversion in a two-mode PPLN waveguide, here we report the extension of this work into the single-photon-level regime. The signal (1540 nm) in either a single mode (TM00 or TM01) or a superimposition mode (TM00+TM01, TM00+iTM01) of the waveguide is selectively up-converted into TM01 SFG mode, by interacting with an appropriate pump mode (1560 nm). An accurate measurement of the single-photon-level SFG signals requires thorough filtering of the unwanted photons contributed by the second harmonic of the pump, residual pump noise extending to the signal band, and the Raman noise generated in the waveguide. We have investigated these unwanted photon sources and suppressed them by a combination of thin-film-interference and volume-Bragg-grating filters. Resulting single-photon-counting measurements show >70% internal conversion efficiency, better than -12dB crosstalk, and >100 ratio of the signal to background photon counts for all selected modes and mode superpositions.

Nonlinear Frequency Generation and Conversion: Materials and Devices•Mar 14, 2018•1 citation

Number Resolving, Mode-Selective Detection of High-Dimensional Correlated Photons

Misagh Izadi, Yuping Huang, Santosh Kumar +5 more

High-dimensional encoding in time-frequency and photon-number degrees of freedom promises photon-efficient quantum communication, but requires detectors that are both temporal-mode selective and photon-number resolving. Here we demonstrate time-correlated single-photon detection combining both capabilities. A train of shaped pump pulses drives quantum frequency up-conversion to select a chosen temporal mode, and the converted photons are counted with a photon-number-resolving detector. Applying to a photon-pair source by spontaneous parametric downconversion into signal and idler bands, we demonstrate direct sampling of the high-dimensional correlated quantum states on compound time-frequency and photon number bases. Our measurements show that the up-converted photons in each band exhibit thermal photon-number statistics, indicating strong single-mode selection. We reconstruct joint temporal intensities conditioned on one and two photon pairs, revealing signal-idler correlations in both time-frequency and photon number. Together, these results establish a unified technology framework linking high-dimensional quantum correlations, mode-selective photon measurement, and photon-number resolved detection. This approach provides a route to characterizing multimode photon-pair sources and to larger time-frequency and photon-number alphabets for high-dimensional quantum communication and information processing.

•Oct 28, 2026•0 citations

Number Resolving, Mode-Selective Detection of High-Dimensional Correlated Photons

Misagh Izadi, Yuping Huang, Santosh Kumar +5 more

High-dimensional encoding in time-frequency and photon-number degrees of freedom promises photon-efficient quantum communication, but requires detectors that are both temporal-mode selective and photon-number resolving. Here we demonstrate time-correlated single-photon detection combining both capabilities. A train of shaped pump pulses drives quantum frequency up-conversion to select a chosen temporal mode, and the converted photons are counted with a photon-number-resolving detector. Applying to a photon-pair source by spontaneous parametric downconversion into signal and idler bands, we demonstrate direct sampling of the high-dimensional correlated quantum states on compound time-frequency and photon number bases. Our measurements show that the up-converted photons in each band exhibit thermal photon-number statistics, indicating strong single-mode selection. We reconstruct joint temporal intensities conditioned on one and two photon pairs, revealing signal-idler correlations in both time-frequency and photon number. Together, these results establish a unified technology framework linking high-dimensional quantum correlations, mode-selective photon measurement, and photon-number resolved detection. This approach provides a route to characterizing multimode photon-pair sources and to larger time-frequency and photon-number alphabets for high-dimensional quantum communication and information processing.

•Oct 28, 2026•0 citations

Multidimensional mode-separable frequency conversion for high-speed quantum communication

Paritosh Manurkar, Nitin Jain, Michael Silver +5 more

Quantum frequency conversion (QFC) of photonic signals preserves quantum information while simultaneously changing the signal wavelength. A common application of QFC is to translate the wavelength of a signal compatible with the current fiber-optic infrastructure to a shorter wavelength more compatible with high quality single-photon detectors and optical memories. Recent work has investigated the use of QFC to manipulate and measure specific temporal modes (TMs) through tailoring of the pump pulses. Such a scheme holds promise for multidimensional quantum state manipulation that is both low loss and re-programmable on a fast time scale. We demonstrate the first QFC temporal mode sorting system in a four-dimensional Hilbert space, achieving a conversion efficiency and mode separability as high as 92% and 0.84, respectively. A 20-GHz pulse train is projected onto 6 different TMs, including superposition states, and mode separability with weak coherent signals is verified via photon counting. Such ultrafast high-dimensional photonic signals could enable long-distance quantum communication with high rates.

arXiv:1606.07794•Optica•Nov 4, 2016•70 citations
We experimentally demonstrate a mode-selective quantum frequency converter over a compound spatiotemporal Hilbert space. We show that our method can achieve high extinction for high-dimensional quantum state tomography by selectively upconverting the signal modes with a modulated and delayed pump. By preparing the pump in optimized modes through adaptive feedback control, selective frequency conversion is demonstrated with up to 30 dB extinction. The simultaneous operations over high-dimensional degrees of freedom in both spatial and temporal domains can serve as a viable resource for photon-efficient quantum communications and computation.
We experimentally demonstrate a programmable parametric mode sorter of high-dimensional signals in a composite spatiotemporal Hilbert space through mode-selective quantum frequency up-conversion. As a concrete example and with quantum communication applications in mind, we consider the Laguerre-Gaussian and Hermite-Gaussian modes as the spatial and temporal state basis for the signals, respectively. By modulating the spatiotemporal profiles of the up-conversion pump, we demonstrate the faithful selection of single photons in those modes and their superposition modes. Our results show an improvement in the quantum mode-sorting performance by coupling the up-converted light into a single-mode fiber and/or operating the upconversion at the edge of phase matching. By optimizing pump temporal profiles only, we achieve more than 12 dB extinction for mutually unbiased basis (MUB) sets of the spatiotemporal modes. This fully programmable and efficient system could serve as a viable resource for quantum communications, quantum computation, and quantum metrology.
Spatial-mode-selective frequency conversion is potentially useful for both classical and quantum communication applications. By a judicious choice of the quasi-phase-matching period in a Kai(2) multimode waveguide, such conversion can be achieved with high efficiency (close to 100%) and with low crosstalk (< -20 dB). For space-division multiplexing application with classical signals, where each spatial mode represents a separate signal channel, the selective conversion of a spatial mode without disrupting other signal modes can be used for reconfigurable spatial-mode de-multiplexing. This classical de-multiplexing capability can be also extended to the quantum regime, where the quantum state of the signal is preserved during frequency conversion, owing to the unitary nature of the sum-frequency generation (SFG) process. Building upon our previous experimental demonstration of the classical spatial-mode-selective frequency up-conversion in a two-mode PPLN waveguide, here we report the extension of this work into the single-photon-level regime. The signal (1540 nm) in either a single mode (TM00 or TM01) or a superimposition mode (TM00+TM01, TM00+iTM01) of the waveguide is selectively up-converted into TM01 SFG mode, by interacting with an appropriate pump mode (1560 nm). An accurate measurement of the single-photon-level SFG signals requires thorough filtering of the unwanted photons contributed by the second harmonic of the pump, residual pump noise extending to the signal band, and the Raman noise generated in the waveguide. We have investigated these unwanted photon sources and suppressed them by a combination of thin-film-interference and volume-Bragg-grating filters. Resulting single-photon-counting measurements show >70% internal conversion efficiency, better than -12dB crosstalk, and >100 ratio of the signal to background photon counts for all selected modes and mode superpositions.
High-dimensional encoding in time-frequency and photon-number degrees of freedom promises photon-efficient quantum communication, but requires detectors that are both temporal-mode selective and photon-number resolving. Here we demonstrate time-correlated single-photon detection combining both capabilities. A train of shaped pump pulses drives quantum frequency up-conversion to select a chosen temporal mode, and the converted photons are counted with a photon-number-resolving detector. Applying to a photon-pair source by spontaneous parametric downconversion into signal and idler bands, we demonstrate direct sampling of the high-dimensional correlated quantum states on compound time-frequency and photon number bases. Our measurements show that the up-converted photons in each band exhibit thermal photon-number statistics, indicating strong single-mode selection. We reconstruct joint temporal intensities conditioned on one and two photon pairs, revealing signal-idler correlations in both time-frequency and photon number. Together, these results establish a unified technology framework linking high-dimensional quantum correlations, mode-selective photon measurement, and photon-number resolved detection. This approach provides a route to characterizing multimode photon-pair sources and to larger time-frequency and photon-number alphabets for high-dimensional quantum communication and information processing.
High-dimensional encoding in time-frequency and photon-number degrees of freedom promises photon-efficient quantum communication, but requires detectors that are both temporal-mode selective and photon-number resolving. Here we demonstrate time-correlated single-photon detection combining both capabilities. A train of shaped pump pulses drives quantum frequency up-conversion to select a chosen temporal mode, and the converted photons are counted with a photon-number-resolving detector. Applying to a photon-pair source by spontaneous parametric downconversion into signal and idler bands, we demonstrate direct sampling of the high-dimensional correlated quantum states on compound time-frequency and photon number bases. Our measurements show that the up-converted photons in each band exhibit thermal photon-number statistics, indicating strong single-mode selection. We reconstruct joint temporal intensities conditioned on one and two photon pairs, revealing signal-idler correlations in both time-frequency and photon number. Together, these results establish a unified technology framework linking high-dimensional quantum correlations, mode-selective photon measurement, and photon-number resolved detection. This approach provides a route to characterizing multimode photon-pair sources and to larger time-frequency and photon-number alphabets for high-dimensional quantum communication and information processing.
Quantum frequency conversion (QFC) of photonic signals preserves quantum information while simultaneously changing the signal wavelength. A common application of QFC is to translate the wavelength of a signal compatible with the current fiber-optic infrastructure to a shorter wavelength more compatible with high quality single-photon detectors and optical memories. Recent work has investigated the use of QFC to manipulate and measure specific temporal modes (TMs) through tailoring of the pump pulses. Such a scheme holds promise for multidimensional quantum state manipulation that is both low loss and re-programmable on a fast time scale. We demonstrate the first QFC temporal mode sorting system in a four-dimensional Hilbert space, achieving a conversion efficiency and mode separability as high as 92% and 0.84, respectively. A 20-GHz pulse train is projected onto 6 different TMs, including superposition states, and mode separability with weak coherent signals is verified via photon counting. Such ultrafast high-dimensional photonic signals could enable long-distance quantum communication with high rates.